Japanese Patent Application (OPI) No. 41734/76 (the term "OPI" as used herein refers to a "published unexamined Japanese patent application") describes that disazo dyes represented by the following general formula (II): ##STR3## wherein K represents a coupling component group, R.sup.13 represents a C.sub.1 -C.sub.4 alkylaryl group, a C.sub.1 -C.sub.4 alkoxycarbonyl group or a hydrogen atom, R.sup.14 represents an aryl group, a C.sub.1 -C.sub.4 alkoxycarbonyl group, COW.sub.1 W.sub.2 or a cyano group, X.sup.1 and X.sup.2 each represents a hydrogen atom, a chlorine atom, a bromine atom, a cyano group, CF.sub.3, a nitro group, a C.sub.1 -C.sub.4 alkyl group, a C.sub.1 -C.sub.4 alkoxy group, a phenyl group, a C.sub.1 -C.sub.4 alkylcarbonyl group, a C.sub.1 -C.sub.4 alkoxycarbonyl group, a C.sub.1 -C.sub.6 alkylsulfonyl group, an arylsulfonyl group, a benzylsulfonyl group, COOH, SO.sub.2 NW.sub.1 W.sub.2 or CONW.sub.1 W.sub.2, provided that they do not represent hydrogen atoms at the same time, X.sup.3 represents a hydrogen atom, a C.sub.1 -C.sub.4 alkyl group, a C.sub.1 -C.sub.4 alkoxy group, a chlorine atom, a bromine atom or a cyano group, X.sup.4 represents a hydrogen atom, a methyl group, a chlorine atom or a bromine atom, and W.sub.1 and W.sub.2 each represents H, a C.sub.1 -C.sub.4 alkyl group or a hydroxyethyl group or, when taken together, W.sub.1 and W.sub.2 form a residue of saturated 5- or 6-membered hetero ring, can dye polyester fibers to a violet to bluish green color. However, the Japanese OPI does not describe whether or not the dyes can dye cellulose-containing fibers.
On the other hand, Japanese Patent Application Nos. 10690/81 and 10691/81 describe as dyes for dyeing polyester fibers the dyes represented by the following structural formulae (III-A) and (III-B): ##STR4## which are the same type of dyes as that described in the above Japanese OPI.